Artificial Consortia of Bacillus Amyloliquefaciens HM618 and Bacillus Subtilis for Utilizing Food Waste to Synthetize Iturin A

Abstract

Food waste is a kind of biodegradable organic resource. It can be degraded into the small energy molecules for providing precursors to synthetize iturin A, which is a kind of lipopeptide with broad-spectrum antifungal activity for widely applying in biocontrol of the plant disease. However, the lower yield and higher cost during producing iturin A limit its application. In this study, the recombinants of Bacillus subtilis producing lipase and amylase were constructed to utilize food waste for producing iturin A under the consortium with Bacillus amyloliquefaciens HM618 produced iturin A and the engineering B. subtilis. The results showed that recombinant strain WB-A13 had the highest amylase activity of 23406.4 U/mL, and the lipase activity of WB-L01 was 57.5 U/mL. When HM618 was co-cultured with the engineering strain WB800N-AmyE or WB800N-Lip, the relatively highest yield of iturin A reached to 7.66 mg/L in co-cultured fermentation of consortium with HM618 and WB-A14, which was increased 32.9% compared to that of HM618 under pure culture. Under three-strains consortium containing HM618, WB-L02 and WB-A14, the yield of iturin A reached 8.13 mg/L, which was 38.8% higher than the control when the initial size OD600 of above three strains was 0.2, 0.15 and 0.15 respectively. Taken together, artificial consortium of B. amyloliquefaciens and the recombinant B. subtilis can better bioconvert food waste into iturin A, which provides a new strategy for the high-value utilization of food waste.